Well, try to make it work without the last RC...it will give you more life.
I am still listening, switching back and forth, but it seems that I hear the following:
- g2/g3 as Anodes: Very, very precise. But as well a bit dry.
- g2/g3/anode as anodes: More body and sould, more "tone", but a certain smearing takes place, not as precise as above, it is like you listento two tube with two different sounds in parallel.
- g2/anode together, g3 not connected at all: You got the tone and you got precision. No smearing. Not as dry and precise as g2/g3 only, but maybe the version I like best in the end.
I need to listen further, but the switches you saw in the picture allow me to do a A/B test within a minute.
Ne ertheless, its time to compare all of this with a real DHT. 801a is waiting. Coleman regs will get bigger heatsinks...
I am still listening, switching back and forth, but it seems that I hear the following:
- g2/g3 as Anodes: Very, very precise. But as well a bit dry.
- g2/g3/anode as anodes: More body and sould, more "tone", but a certain smearing takes place, not as precise as above, it is like you listento two tube with two different sounds in parallel.
- g2/anode together, g3 not connected at all: You got the tone and you got precision. No smearing. Not as dry and precise as g2/g3 only, but maybe the version I like best in the end.
I need to listen further, but the switches you saw in the picture allow me to do a A/B test within a minute.
Ne ertheless, its time to compare all of this with a real DHT. 801a is waiting. Coleman regs will get bigger heatsinks...
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Very interesting..... I have a plate choke on my 2P29L input stage which is 50H and 750R, no markings on it but I'm guessing 20mA. Looks like I could try out the 4P1L as above. I have to say the 2P29L is sounding very good, though.
Makes me wonder if the same kind of experiments should be carried out on the 2P29L. Not aware anybody did that yet.
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I only experimented with the 4P1L so far. I prefer the G2+G3 as anode connection overall.
I think the 2P29L should work, however it has less than 1W on screen dissipation. It will require a follower at the output probably. Still need to test the linearity but would expect is good as in triode.
Also, someone has to sacrifice a valve and smash it to see the screen mesh structure
Ale
I tried both G2 and G2+G3 as anode with my 5ma LL1680 filament bias, difference too small to hear in my system. But bias point make bigger difference, with similar Ik, a bit drier sound with higher than 130V B+.
I followed Ale's advise on the raw supply and basically built his LCLCraw suuply for the Coleman regs I am using. It needed about 20hours of burn in as I built a complete 2.set of raw supplies to be able to switch between original crc and lclc.
Result:
Treble and resolution is there as it was before, but a certain graininess is gone. Tonal richness improved tough, much more micro-information are there next to great macro-dynamics. Frightening dynamics. It is like someone has pressed a loudness button and a Dolby C button at the same time.
Space became deeper and everything much more natural, more information for sure. A bit like you would expect going from idht to dht.
For my ears a must. Puuuuh even more parts just to heat the god-damn thing...but no choice. One day I will try purely passive without the Coleman regs and see what happens then (as my raw supply is now 0.5h-33000uf-0.01h-33000uF...should be quiet even without a reg I guess).
Result:
Treble and resolution is there as it was before, but a certain graininess is gone. Tonal richness improved tough, much more micro-information are there next to great macro-dynamics. Frightening dynamics. It is like someone has pressed a loudness button and a Dolby C button at the same time.
Space became deeper and everything much more natural, more information for sure. A bit like you would expect going from idht to dht.
For my ears a must. Puuuuh even more parts just to heat the god-damn thing...but no choice. One day I will try purely passive without the Coleman regs and see what happens then (as my raw supply is now 0.5h-33000uf-0.01h-33000uF...should be quiet even without a reg I guess).
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For my ears a choke is a must too. I just use LCRC - single choke - but try and make that choke as large as possible. I have quite a few big chokes of 280mH at 2.7A, and I use those for the PSE 4P1L output stage. For the input stage 2P29L I use Hammond 158T, which is 1H at 300mA. As said above, the sound is audibly smoother with a choke input. Yes, it's an extravagance but we're in the game of maximising everything with DHTs. The circuits themselves are ridiculously simple, but the filament supplies are almost amplifiers in themselves. I have them all in separate boxes with 4 pin XLR leads. Just a different way of thinking overall.
As I've said elsewhere, I'm really pleased with 2P29L into two of Hammond 126C in series, just used as plate chokes. Ends up being large and heavy with 4 of the things - I take the end bells off and mount them in the chassis. But it's worth it. I have a 10Y version with the same 4 of 126C but for daily use I'm fine with 2P29L, and it's on 24/7. 2P29Ls are cheap and good, just like the 4P1L.
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Hi Andy,
Thanks for your post...I am currently using Lundahl LL2733...one per channe plus two small CmRR chokes like Ale, which are really cheap, so two raw supplies in total with two regs per channel, so four regs in total as my DAC is balanced output (ess9018).
Next project will be a fully balanced, fully DHT, 814 power amp...I was just getting nervous as I thought about how many expensive Lundahl Chokes I would have to buy, but maybe Hammond is a good option, too...four output tubes DHT, four driver...maybe four input...twelve regs !!!
May I ask you for a comparison between 4p1l, 2p29l and 10Y ? I was planning to exchange my 4p1L and see what will happen with some 10Y/801A...is it worth the trouble ? How did you like it and would characterize one and the other ? The tubes are already there, so I will do it anyhow, but a sneak-preview would be nice to get some motivation...
Thanks for your post...I am currently using Lundahl LL2733...one per channe plus two small CmRR chokes like Ale, which are really cheap, so two raw supplies in total with two regs per channel, so four regs in total as my DAC is balanced output (ess9018).
Next project will be a fully balanced, fully DHT, 814 power amp...I was just getting nervous as I thought about how many expensive Lundahl Chokes I would have to buy, but maybe Hammond is a good option, too...four output tubes DHT, four driver...maybe four input...twelve regs !!!
May I ask you for a comparison between 4p1l, 2p29l and 10Y ? I was planning to exchange my 4p1L and see what will happen with some 10Y/801A...is it worth the trouble ? How did you like it and would characterize one and the other ? The tubes are already there, so I will do it anyhow, but a sneak-preview would be nice to get some motivation...
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Well, I'd make as much as possible SE myself. Always preferred SE, particularly on vocals and I listen to more vocal music than anything else. If more power was needed I'd go PSE before PP or PPP. If it needed PP outputs, I'd use an interstage phase splitter. That's my view, having built a complete balanced system. I built a balanced 01A preamp which was just too complex for the results I got. I then built a balanced amp of 26 into 4P1L into 2a3PP. It's still on the shelf - two huge monobloks. Never sounded better than PSE. At some point I'll convert it back to SE input and PP outputs with a LL1660 or something similar. The thing is that with my builds the filament supplies are so big and heavy (with my 2.7A chokes) that the fewer there are the better I like it. If the "excuse" for PP input is a PP DAC, then I'd find some way around that rather than compromise the amp. That's my overall view. As it is my simple 2 stage amp is in 6 separate boxes. Enough!
In terms of tubes, I've retired the 26. I like the 46 but can't see where to use it. I really, really like the 01A as much as anything but at 3mA I can't see where to use it. The 4P1L is my standard output but I think 4P1L into 4P1L isn't ideal. I like the 10Y a lot but never end up using it. This may sound perverse - maybe I'm just a miser at heart and am hoarding them for when I'll get a good return on my stock. I leave my system on 24/7 so I'm happier with cheap tubes. Then along came the 2P29L at Ale's suggestion. This is cheap and sounds very good - it has a lot of detail and quite a robust sound. It doesn't have the magic of the 01A in the treble - nothing quite does. But I can run it at 15mA and it drives the 4P1L outputs, and it sounds very good into 2x126C. So that has ended up as my choice for now at least. The 10Y is probably a better tube overall - if money is no object. But not so much better that I can't live with the 2P29L which is 80% to 90% what the 10Y can do. If it were a 3 stage amp I'd start with a 01A, no contest. Then toss up between 2p29L, 4P1L and 10Y as a driver. 15mA for the 2P29L and up to 30mA or more for the 4P1L and 10Y. They would all be in filament bias of course, and this being the case the 2P29L is easiest to implement, then the 4P1L, then the 10Y where we get some more heat dissipation and larger chokes and transformers.
Hmmm...I just gotthe new Ess9038 in the house which will output I believe 64mA differential in PP...maybe I wil drive a transformer with it to convert differential signal to SE and have an easier life overall...I have to think about it and which transformer would really be the right one.
I believe I tried many years ago a 1794 Dac with a transformer...sounded tired, but I believe that Dac had only 2mA output...
I believe I tried many years ago a 1794 Dac with a transformer...sounded tired, but I believe that Dac had only 2mA output...
Mr. Evans,
I hope you have not already answered this or it could be I am the only one who does not know how you are wiring the Hammond transformers as plate chokes.
Seems there are four equal windings. Are you using only one, or all in series or some other arrangement?
Thanks and Happy New Year,
I hope you have not already answered this or it could be I am the only one who does not know how you are wiring the Hammond transformers as plate chokes.
Seems there are four equal windings. Are you using only one, or all in series or some other arrangement?
Thanks and Happy New Year,
Hi Rick,
I believe that the126C has only one primary with 106H...(http://www.mouser.com/ds/2/177/5C_124_126-32259.pdf). I believe Andy had two of these around and connected two primaries in series and just did not used the secondaries, so a hefty 212H...
Hi Andy,
I have just changed the RC driver stage (e182cc) towards LC with an LL1668am...to see what RC vs. LC does...switchable, so I can compare withing seconds (at the same anode voltage /current as the is a LTP with a CCS).
Does the choke need a burn-in in your experience ? I would guess so...sounded quiet weird in the beginning and starts to improve...first impression: With resistor finer painted picture and with choke more dynamic, but not as fine grain as with resistor...but this have been the first 30min...
I believe that the126C has only one primary with 106H...(http://www.mouser.com/ds/2/177/5C_124_126-32259.pdf). I believe Andy had two of these around and connected two primaries in series and just did not used the secondaries, so a hefty 212H...
Hi Andy,
I have just changed the RC driver stage (e182cc) towards LC with an LL1668am...to see what RC vs. LC does...switchable, so I can compare withing seconds (at the same anode voltage /current as the is a LTP with a CCS).
Does the choke need a burn-in in your experience ? I would guess so...sounded quiet weird in the beginning and starts to improve...first impression: With resistor finer painted picture and with choke more dynamic, but not as fine grain as with resistor...but this have been the first 30min...
Hi Frank,
Just found the time to remove 1 X 45uf Cap & 120R resistor from Power Supply & You are certainly right about the sound coming to life, much more holographic & airy sounding, it's has a free'er sound. I am also playing with current settings at the moment.
Hi Andy,
I have now built quite a few different ones now & my last 2 were 4P1L (in screen mode as Ale says) & 2P29L, the latter believe it or not I couldn't kill the microphony, I did strip the canisters off though, which Ale also did, this led me to go back to concentrate on the 4P1L, which to my ear sounds great using this method through Ale's Gyrator Boards & running at 16mA, this seems to be the sweet spot in my setup. I have also built 26, 01a & 2C22 in the past, I kept the 01a as it's just the best sounding IMHO. Although the 2C22 isn't a DHT, I found it to be truly excellent if implemented properly (sold now)!